Hyper armor can stay as long as it only works on heavy attacks vs light attacks.
Meaning only heavy attacks can have hyper armor, and only light attacks would not stop them. Heavies would still interrupt a hyper armor attack. I think this would balance it well enough.
Maybe they could make it so that hitting a hyperarmored opponent during their attack would decrease the damage of that hyperarmor attack.
I think that hyperarmor should resist all attacks but the unblockables (every kind), since they are the strongest attacks of certain heroes, and it's dumb that a character just tanks it through. Maybe the heavy attack would be a bit too much, but the unblockable is the least. And there should be less in the game than currently is (mainly the slower heroes should have ha, not berserker).
Removing Hyperarmor isn't a fix, especially on most heroes who use it. They need it to trade hits. IMO, hyperarmor is pretty good right now. All heroes who use it, use it in a way that fits their playstyle. And are you seriously complaining about Shugoki? Whose kit and overall state is ****? Get out of here. (I play Lawbringer and Cent, both of which who do not have Hyperarmor except on one attack, so I'm not being biased here)
Hyper armor as a mechanic is pretty good as it is. It encourages trading on characters who generally lack the speed to interrupt their opponents and have the health/damage to do so.
Kensei personally should not have hyper armor on many, if any of his mixup moves. They're very fast and it doesn't make much sense to have a trading move be that fast anyway.